1. Field of the Invention
This invention relates to an automated or robotised material handling equipment intended more particularly for storehouses in which miscellaneous articles or products are stored, this equipment being suitable for either restocking, or re-assembling articles picked up in the storehouse for constituting groups of articles corresponding to a predetermined or preselected order.
This invention is applicable more particularly but not exclusively in the storage premises of the type existing notably in mail-order stores of the kind offering for sale to their customers a great number of articles of many different types which are subsequently grouped and then dispatched as a function of the specific order received from each customer. However, other applications may be contemplated, for instance in the storage of textile articles or other products.
2. The Prior Art
At the present time it is known to store a great number of articles in shops by using racks or like receptacles disposed in rows along the shop's lanes, each rack receiving unitary storage bins containing the objects or articles to be stored.
Usually, storehousemen must move about in the store for picking up one or more articles from the various storage bins.
According to the kind of articles to be handled, these articles can be picked up with the assistance of fork lift trucks driven by the storehouseman along the lanes, the truck handling the bins filled with articles.
Then, the necessary articles must be pick up from the bins at a re-grouping station from which the articles are directed to a dispatching station or department whereat the orders of each customer are regrouped and shipped.
This nearly manual method involves a great number of manual handling operations and becomes rapidly restricted to relatively small stores having a relatively small number of different articles to be managed at a moderate recurrence rate.
In fact, when the number of articles kept in stock and the number of handling operations are high, the necessary staff increases considerably, and each operator must dispose of adequate material handling means and furthermore have a clear knowledge of the position of each article in the store. Now this will obviously reduce the efficiency of the system and the rate of dispatching, while increasing abnormally the cost of each dispatched article on account of the excessive cost of handling operations.
It is for this reason that certain business companies decided in recent times to use manually operated trucks of particular design, which are adapted to travel along a shop lane lined with racks. These trucks comprise as a rule a frame guided by an under-the-floor or overhead rail, and a lift platform from which the warehouseman can control the handling operations. In addition, to avoid to and fro movements under certain circumstances a plurality of bins can be placed on this platform for regrouping several orders without moving several times along the store lane.
Notwithstanding certain advantageous features in comparison with the manual handling system, these trucks are attended by many inconveniences, such as requiring an operator for driving each manual truck, the necessity for the operators to have a complete knowledge of the store, and assigning a predetermined lane to a given truck. Under these conditions, the handling of goods in the storehouse lacks flexibility and gives rise to serious inconveniences from the dual point of view of efficiency and cost.
To improve the above-described manual trucks, certain manufacturers have introduced automatic control means for controlling the handling operations according to a predetermined program.
With power trucks of this type it is possible to locate and approach a bin containing for example spare parts at a well-defined location of the racks concerned, whereafter, to avoid jammings the thus picked up bins are deposited by the truck in a central lane extending across the lanes along which the truck is caused to travel, said central lane comprising as a rule endless belt convreyors so that the articles can easily be directed to a regrouping station.
Obviously, with these considerably improved transfer and storage systems the handling operations can be eased in certain cases without being entirely satisfactory, for various reasons.
More particularly, these transfer means are adapted as a rule to handle only one reference article at a time, for example by complete pallets or bins loaded with several objects. They are not capable, under any circumstance, to pick up separately one of the objects disposed on said pallet or in said bin.
Moreover, only a few material handling storage systems are provided with means for temporarily storing goods thereon, because the bins, pallets and articles to be transferred are generally bulky and heavy. Therefore, each truck must make several shuttle movements during its operation, thus increasing detrimentally the time necessary for carrying out the material handling cycle.
Another important drawback observed with the above-mentioned known truck systems lies in the fact that they are fixed and must compulsorily serve a single and predetermined lane in the store. In fact, these known transfer and storage means comprise a truck guided on the floor by rolling on one or more rails parallel to and spaced from the shelving or racks.
Now, in case of failure of the goods transfer system, the complete storehouse is held up because the stuck truck will prevent the passage of a break-down repair truck, if any, inasmuch as the implementation of this repair truck would be problematical owing to the necessity of providing a dual electric system.
In addition, it is also worth pointing out that, due to the rigidity of the material handling systems, a store robotised by using goods handling trucks is designed for operation at a predetermined rate that cannot be changed as a function of the number of orders to be dealt with. Therefore, in certain industries where the turn-round is either below, or above, an average rate due to a decrease or an increment in the number or orders to be executed, exploiting a known automated material handling system is neither adequate nor advantageous.